Etiology of malocclusion

Etiology of MalocclusionEtiology of Malocclusion
Classification of malocclusionClassification of malocclusion
Drawbacks of Angle classificationDrawbacks of Angle classification
Only dental relationship considered.Only dental relationship considered.
First molars given the maximum priority.First molars given the maximum priority.
Only the sagittal relationship is consideredOnly the sagittal relationship is considered
Not applicable to the deciduous dentitionNot applicable to the deciduous dentition
Does not grade the severity of the conditionDoes not grade the severity of the condition
Only static in natureOnly static in nature
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Lischer’s modificationLischer’s modification
Neutro-occlusion – Class INeutro-occlusion – Class I
Disto-occlusion – Class IIDisto-occlusion – Class II
Mesio-occlusion – Class IIIMesio-occlusion – Class III

Lischer’s modificationLischer’s modification
Linguo or labioversionLinguo or labioversion
Mesio or distoversionMesio or distoversion
Infra or supraversionInfra or supraversion
TorsiversionTorsiversion
PerversionPerversion
TransversionTransversion

Dewey’s classification (modification of Class I)Dewey’s classification (modification of Class I)
Type I – crowded anterior teethType I – crowded anterior teeth
Type II – Upper incisors in labioversionType II – Upper incisors in labioversion
Type III – Anterior crossbiteType III – Anterior crossbite
Type IV – Posterior crossbiteType IV – Posterior crossbite
Type V - Only molars in mesioversionType V - Only molars in mesioversion

Dewey’s classification (modification of ClassDewey’s classification (modification of Class
III)III)
Type I – Normal incisor overlappingType I – Normal incisor overlapping
Type II – Edge to edge incisor relationType II – Edge to edge incisor relation
Type III – Anterior crossbiteType III – Anterior crossbite

Simon’s ClassificationSimon’s Classification
Paul Simon was the first person to recordPaul Simon was the first person to record
malocclusion in all three dimensions. He usedmalocclusion in all three dimensions. He used
an apparatus known as the ‘Gnathostat’ toan apparatus known as the ‘Gnathostat’ to
record the positions of the teeth.record the positions of the teeth.

Terms used by SimonTerms used by Simon
Contraction / DistractionContraction / Distraction
Attraction / AbfractionAttraction / Abfraction
Protraction / RetractionProtraction / Retraction

Ackerman and Proffit’s ClassificationAckerman and Proffit’s Classification
This classification involved as subdivision ofThis classification involved as subdivision of
tooth alignments into 8 categories.tooth alignments into 8 categories.
These includeThese include
1)1)Intra-arch alignmentIntra-arch alignment
2)2)ProfileProfile
3)3)TransverseTransverse
4)4)SagittalSagittal
5)5)VerticalVertical www.indiandentalacademy.comwww.indiandentalacademy.com

Ackerman and Proffit’s ClassificationAckerman and Proffit’s Classification
This classification involved as subdivision ofThis classification involved as subdivision of
tooth alignments into 8 categories.tooth alignments into 8 categories.
6) Trans-sagittal6) Trans-sagittal
7) Sagitto-vertical7) Sagitto-vertical
8) Trans-vertical8) Trans-vertical
9) Trans-sagito-vertical9) Trans-sagito-vertical

Group 3
Transverse Deviation (Lateral)
-Buccal
-Palatal
- Unilateral
- Bilateral
-Dental
-Skeletal
Alignments:
-Profile:
-TYPE
Group 4
Sagittal Deviation (A-P)
- Class I Ant.
Displacement
-Class II Division 1
Division 2
- Class III
-Dental
-Skeletal
-Alignment: Profile:
CLASS
Group 5
Vertical Deviation
-Open Bite anterior
Posterior
-Deep Bite, Anterior
-Collapsed Bite, Posterior
-Dental
-Skeletal
Alignments:
Profile:
BITE DEPTH
Group 6
Trans-Sagittal
Alignment:
Profile:
Type:
Class:
Group 8
Vertico-Transverse
Alignment:
Profile:
Bite Depth
Group7
Sagitto-Vertical
Alignment:
Profile:
Class:BiteDepth
Group 9
Trans-Sagitto
Alignment:
Profile:
Type::Class:
Bite Depth
Group 2
Profile
Alignment:
-Convex
-Straight
-Concave
-Anterior Divergent
-Posterior Divergent
Group 1
Intra Arch Alignment
Symmetry (occlusal
View)
-Ideal
-Crowding
-Spacing

Normal/Ideal Occlusion v/s Malocclusion

Malocclusion is a developmental problem
resulting from the interplay of several
factors that often cannot be isolated

Classification of malocclusion
a) Skeletal
b) Dental
c) Combination
These in turn, could be in any of the three
planes of space.

a) Skeletal - Sagittal – Class I, II or III

Vertical Skeletal– HypodivergentVertical Skeletal– Hypodivergent
and Hyperdiverdivergentand Hyperdiverdivergent

Vertical dental malocclusionsVertical dental malocclusions
Deep Bite or Open BiteDeep Bite or Open Bite

Transverse Skeletal Malocclusions – Facial
Asymmetry

Causes of malocclusion
A. Hereditary
B. Environmental

Classifications of Etiologic FactorsClassifications of Etiologic Factors
General FactorsGeneral Factors
 1.1. Heredity (the inherited pattern)Heredity (the inherited pattern)
 2.2. Congenital defects (cleft palate, torticollis, cleidocranialCongenital defects (cleft palate, torticollis, cleidocranial
 dysostosis, cerebral palsy, syphilis, etc.)dysostosis, cerebral palsy, syphilis, etc.)
 3.3. EnvironmentEnvironment
– a.Prenatal (trauma, matemal diet, maternal metabolism,a.Prenatal (trauma, matemal diet, maternal metabolism,
 German measles, etc.)German measles, etc.)
bb..Postnatal (birth injury, cerebral palsy, TMJ injury, etc.)Postnatal (birth injury, cerebral palsy, TMJ injury, etc.)
 4.4. Predisposing metabolic climate and diseasePredisposing metabolic climate and disease
– a.a. Endocrine imbalanceEndocrine imbalance
– b.b. Metabolic disturbancesMetabolic disturbances
– c.c. Infectious diseases (poliomyelitis, etc.)Infectious diseases (poliomyelitis, etc.)
 5.5. Dietary problems (nutritional deficiency)Dietary problems (nutritional deficiency)

6. Abnormal pressure habits and functional aberrations6. Abnormal pressure habits and functional aberrations
a.a. Abnormal suckling (forward mandibular posture,Abnormal suckling (forward mandibular posture,
nonphysiologic nursing, excessive buccal pressures, etc.,)nonphysiologic nursing, excessive buccal pressures, etc.,)
b.b. Thumb and finger suckingThumb and finger sucking
c.c. Tongue thrust and tongue suckingTongue thrust and tongue sucking
d.d. Lip and nail bitingLip and nail biting
e.e. Abnormal swallowin habits (improper deglutition)Abnormal swallowin habits (improper deglutition)
f.f. Speech defectsSpeech defects
g.g. Respiratory abnormalities (mouth breathing etc.)Respiratory abnormalities (mouth breathing etc.)
h.h. Tonsils and adenoids (Compensatory tongue position)Tonsils and adenoids (Compensatory tongue position)
i.i. I. Psychogenic tics and bruxismI. Psychogenic tics and bruxism
7.7. PosturePosture
8.8. Trauma and accidentsTrauma and accidents

Local factors:Local factors:
1.1. Anomalies of numberAnomalies of number
a.a. Supernumerary teethSupernumerary teeth
b.b. Missing teeth (congenital absence or loss due toMissing teeth (congenital absence or loss due to
accidents, caries etc.)accidents, caries etc.)
2.2. Anomalies of tooth sizeAnomalies of tooth size
3.3. Anomalies of tooth shapeAnomalies of tooth shape
4.4. Abnormal labial frenum; mucosal barriersAbnormal labial frenum; mucosal barriers
5.5. Premature lossPremature loss
6.6. Prolonged retentionProlonged retention
7.7. Delayed eruption of permanent teethDelayed eruption of permanent teeth
8.8. Abnormal eruptive pathAbnormal eruptive path
9.9. AnkylosisAnkylosis
10.10. Dental cariesDental caries
11.11. Improper dental restorations.Improper dental restorations.

Moyers lists seven “causes and clinicalMoyers lists seven “causes and clinical
entities”entities”
1.1. HeredityHeredity
a.a. Neuromuscular systemNeuromuscular system
b.b. BoneBone
c.c. TeethTeeth
d.d. Soft parts (other than nerve and muscle)Soft parts (other than nerve and muscle)
1.1. Developmental defects of unknown originDevelopmental defects of unknown origin
2.2. TraumaTrauma
a. prenatal trauma and birth injuriesa. prenatal trauma and birth injuries
b. Postnatal traumab. Postnatal trauma

4. Physical agents4. Physical agents
a. Prenatala. Prenatal
b. Postnatalb. Postnatal
5. Habits (thumb and finger sucking, tongue5. Habits (thumb and finger sucking, tongue
sucking lip biting, etc)sucking lip biting, etc)
6. Disease6. Disease
a. Systemic diseasesa. Systemic diseases
b. Endocrine disordersb. Endocrine disorders
c. Local diseases.c. Local diseases.
7. Malnutrition.”7. Malnutrition.”

Causes of malocclusion –
Sizes of the individual jaw, the orientation
and their placement,Tooth shape, Tooth
size are largely inherited.
On the contrary, the dental features like
overjet, crowding/ spacing, individual
tooth crossbite etc. have an equal
environmental factor as a causative.

a) Congenital :

a) Congenital : The commonest congenital
anomaly affecting the craniofacial
region is Cleft lip and palate.
Features of this include : Midface
deficiency, nasal deformity, cleft of the
lip and/ or palate, contracted upper
arch, missing lateral incisor(s) and
supernumeraries

b) As a part of certain syndromes :

Causes of malocclusion – A case of
ectodermal dysplasia

Specific causes of malocclusion- Alteration
in the equilibrium
a) Developmental

in the equilibrium
b) Habits

in the equilibrium
b) Habits– ProlongedThumb / digit sucking

in the equilibrium
b) Habits– Prolonged Mouth breathing

in the equilibrium
b) Habits– Effects on dentition that are
common to mouth breathing and digit
sucking

in the equilibrium

in the equilibrium
b) Habits– Tongue thrusting

in the equilibrium
b) Habits– Tongue thrusting - control

Local causes
1.1. Anomalies of numberAnomalies of number
a.a. Supernumerary teethSupernumerary teeth
b.b. Missing teeth (congenital absence or loss due to accidents,Missing teeth (congenital absence or loss due to accidents,
caries etc.)caries etc.)
2.2. Anomalies of tooth size and shapeAnomalies of tooth size and shape
3. Premature loss3. Premature loss
4. Prolonged retention4. Prolonged retention
5. Delayed eruption of permanent teeth5. Delayed eruption of permanent teeth
6. Abnormal eruptive path6. Abnormal eruptive path

Premature loss of deciduous teeth.
Incisors : Esthetic concern mainly
Cuspids: Indicator of crowding, midline
shift.
First deciduous molars : mesial shift of
erupting molars,loss of arch length
Second deciduous molars: Mesial tipping
and rotation of the permanent first
molar

Etiology of crowding
Crowding can be either
a) Primary – genetic etiology
b) Secondary – due to local causes

Etiology of crowding
Crowding can be either
a) Primary – genetic etiology
ex: Tooth size- arch length discrepancy
as in macrodontia

Secondary causes of crowding
a) Premature loss of deciduous teeth.
b) Over-retained deciduous teeth.

Postulated causes of late crowding
a) Third molar eruption
b) Lack of attrition of deciduous and
permanent teeth
c) Late growth effects

Causes of spacing
a)Microdontia – genetic
b) Tongue thrust/ Large tongue
c) Pathologic migration in adults
d) Impacted teeth
e) Pathologic lesions such as cysts

Causes of spacing
Pathologic migration in adults

Causes of midline spacing
Physiologic - Normal
- Ugly duckling stage
Macrognathia and/or microdontia
Heredity
High frenal attachment
Impacted teeth
Mesiodens
Proclined anteriors -Habitual
- Large tongue
Midline cysts www.indiandentalacademy.comwww.indiandentalacademy.com

Causes of Crossbites
1.Skeletal
2. Abnormal path of eruption
3. Habits
4. Over-retained deciduous teeth
5. Microglossia

Clinical implications
a) To differentiate between genetic and
environmental
b) To diagnose and plan treatment
c) To prevent, intercept orcorrect
d) Retention based on the cause

The first step towards cure is to know what the
disease is.
- Latin proverb

Etiology of malocclusion

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